Adding the action
If you’ve read my other fail2ban guides you already know I’m using linuxservers letsencrypt container. So there won’t be any walkthrough of installing fail2ban. I will only go through the cloudflare configuration.
Go to your appdata location and find the action.d folder appdata/letsencrypt/fail2ban/action.d
Create a new file called
cloudflare-apiv4.conf and add the following:#
# Author: Gilbn from https://technicalramblings.com
# Adapted Source: https://github.com/fail2ban/fail2ban/blob/master/config/action.d/cloudflare.conf and https://guides.wp-bullet.com/integrate-fail2ban-cloudflare-api-v4-guide/
#
# To get your Cloudflare API key: https://dash.cloudflare.com/profile use the Global API Key
#
[Definition]
# Option: actionstart
# Notes.: command executed once at the start of Fail2Ban.
# Values: CMD
#
actionstart =
# Option: actionstop
# Notes.: command executed once at the end of Fail2Ban
# Values: CMD
#
actionstop =
# Option: actioncheck
# Notes.: command executed once before each actionban command
# Values: CMD
#
actioncheck =
# Option: actionban
# Notes.: command executed when banning an IP. Take care that the
# command is executed with Fail2Ban user rights.
# Tags: IP address
# number of failures
# unix timestamp of the ban time
# Values: CMD
actionban = curl -s -X POST "https://api.cloudflare.com/client/v4/user/firewall/access_rules/rules" \
-H "X-Auth-Email: <cfuser>" \
-H "X-Auth-Key: <cftoken>" \
-H "Content-Type: application/json" \
--data '{"mode":"block","configuration":{"target":"ip","value":"<ip>"},"notes":"Fail2ban <name>"}'
# Option: actionunban
# Notes.: command executed when unbanning an IP. Take care that the
# command is executed with Fail2Ban user rights.
# Tags: IP address
# number of failures
# unix timestamp of the ban time
# Values: CMD
#
actionunban = curl -s -X DELETE "https://api.cloudflare.com/client/v4/user/firewall/access_rules/rules/$( \
curl -s -X GET "https://api.cloudflare.com/client/v4/user/firewall/access_rules/rules?mode=block&configuration_target=ip&configuration_value=<ip>&page=1&per_page=1&match=all" \
-H "X-Auth-Email: <cfuser>" \
-H "X-Auth-Key: <cftoken>" \
-H "Content-Type: application/json" | awk -F"[,:}]" '{for(i=1;i<=NF;i++){if($i~/'id'\042/){print $(i+1);}}}' | tr -d '"' | sed -e 's/^[ \t]*//' | head -n 1)" \
-H "X-Auth-Email: <cfuser>" \
-H "X-Auth-Key: <cftoken>" \
-H "Content-Type: application/json"
[Init]
# Name of the jail in your jail.local file. default = [jail name]
name = default
# Option: cfuser
# Notes.: Replaces <cfuser> in actionban and actionunban with cfuser value below
# Values: Your CloudFlare user account
cfuser = [email protected]
# Option: cftoken (Global API Key)
# Notes.: Replaces <cftoken> in actionban and actionunban with cftoken value below
# Values: Your CloudFlare API key
cftoken = YOUR-API-KEYThe unban curl command from https://guides.wp-bullet.com/integrate-fail2ban-cloudflare-api-v4-guide/ did not work for me but changing it to what this user on serverfault shared did https://serverfault.com/a/912547
Use the “Global API Key“
Updating jail.local
Next is updating or adding your jails in the jail.local file. Go to your appdata location appdata/letsencrypt/fail2ban/ and edit the file called jail.local.
The only thing you really need to add is the action fail2ban will run after it has banned an IP.
Add action = cloudflare-apiv4 in the jails you want to use it on. For me that would be all the jails.
Example:
Default action!
[nginx-http-auth]
enabled = true
filter = nginx-http-auth
action = cloudflare-apiv4
iptables-allports
port = http,https
logpath = /config/log/nginx/error.log
ignoreip = 192.168.1.0/24
[organizrv2-auth]
enabled = true
filter = organizrv2-auth
action = cloudflare-apiv4
iptables-allports
port = http,https
logpath = /fail2ban/organizrLoginLog.json
ignoreip = 192.168.1.0/24Optional: Specifying which site the ban works on
If you have several sites on your Cloudflare account and you want to specify which one the action should work on, you need to change the URL on the actionban line.
Instead of user it needs to say /zones/ and then your zone ID.
actionban = curl -s -X POST "https://api.cloudflare.com/client/v4/zones/YOUR-CLOUDFLARE-ZONE-ID/firewall/access_rules/rules" \
And the same on the actionunban line:
actionunban = curl -s -X DELETE "https://api.cloudflare.com/client/v4/zones/YOUR-CLOUDFLARE-ZONE-ID/firewall/access_rules/rules/$( \
curl -s -X GET "https://api.cloudflare.com/client/v4/zones/YOUR-CLOUDFLARE-ZONE-ID/firewall/access_rules/rules?mode=block&configuration_target=ip&configuration_value=1.2.3.4&page=1&per_page=1&match=all" \
Your zone ID can be found on the overview page on Cloudflare.
I recommend adding a whitelist on your WAN IP so you don’t accidently ban yourself!
You can add the whitelist on Cloudflare by going to Firewall and then Tools. There you can add the access rule.
Nginx
Next up is configuring nginx so that it won’t just ban the Cloudflare CDN IP but the actual IP of the visitor.
Add the following section to your nginx.conf file found in appdata/letsencrypt/nginx/
set_real_ip_from 103.21.244.0/22;
set_real_ip_from 103.22.200.0/22;
set_real_ip_from 103.31.4.0/22;
set_real_ip_from 104.16.0.0/12;
set_real_ip_from 108.162.192.0/18;
set_real_ip_from 131.0.72.0/22;
set_real_ip_from 141.101.64.0/18;
set_real_ip_from 162.158.0.0/15;
set_real_ip_from 172.64.0.0/13;
set_real_ip_from 173.245.48.0/20;
set_real_ip_from 188.114.96.0/20;
set_real_ip_from 190.93.240.0/20;
set_real_ip_from 197.234.240.0/22;
set_real_ip_from 198.41.128.0/17;
set_real_ip_from 2400:cb00::/32;
set_real_ip_from 2606:4700::/32;
set_real_ip_from 2803:f800::/32;
set_real_ip_from 2405:b500::/32;
set_real_ip_from 2405:8100::/32;
set_real_ip_from 2c0f:f248::/32;
set_real_ip_from 2a06:98c0::/29;
real_ip_header X-Forwarded-For;You can set it up as an include like this too:
##
# CF Real IP
##
include /config/nginx/cf_real-ip.conf;
real_ip_header X-Forwarded-For;After that you need to restart the letsencrypt container for the changes to take effect.
Next you can test that it actually works by using a vpn ect and ban yourself. Set bantime to 60 for it to only ban the IP for 1 minute. After the IP is banned you can see the new firewall rule on cloudflare dashboard.
I’ve noticed that with the new API it is much faster in banning and unbanning IP’s! When using the old API it could sometimes take up to 2 minutes for the rule to show in Cloudflare.
Now it’s there in a matter of seconds.
Automatically updating the cf_real-ip.conf
Tronyx over at the discord forums graciously shared his script for updating the Cloudflare ip list. This list is not static and Cloudflare updates it once in a while.
The script below will update the list with any changes in the list of IPs from CF
#!/usr/bin/env bash
curl -s 'https://www.cloudflare.com/ips-v4' > /tmp/cf.txt
curl -s 'https://www.cloudflare.com/ips-v6' >> /tmp/cf.txt
sed 's/^/set_real_ip_from /' /tmp/cf.txt > /tmp/cf2.txt
sed -e 's/$/;/' /tmp/cf2.txt > /home/letsencrypt/config/nginx/cf_real-ip.confI use unraid so I will use the User Scripts plugin to setup a cronjob that will run once a week.
- Go to Settings > User Scripts and click
Add New Script - Give it a name and a description if you want
- Click edit script and add it inside the box.
- You will need to update the path in the last line to you nginx appdata folder
- Set the schedule to weekly and click apply and done.
#!/bin/bash curl -s 'https://www.cloudflare.com/ips-v4' > /tmp/cf.txt curl -s 'https://www.cloudflare.com/ips-v6' >> /tmp/cf.txt sed 's/^/set_real_ip_from /' /tmp/cf.txt > /tmp/cf2.txt sed -e 's/$/;/' /tmp/cf2.txt > /mnt/user/Docker/letsencrypt/nginx/cf_real-ip.conf
For any questions you can find me here:
Sources:
Tronyx 😘 Thank you Tronyx for creating the first draft of the guide.
https://guides.wp-bullet.com/integrate-fail2ban-cloudflare-api-v4-guide
